Which conduit material is specified for weather-exposed service enclosures?

• A. Threaded rigid metal conduit
• B. Nonmetallic conduit
• C. Flexible metallic conduit
• D. PVC conduit

Answer: (A)

Weather-exposed service enclosures need a conduit that provides strong, durable protection against moisture and the elements while also offering a solid grounding path. Threaded rigid metal conduit fits that need best because it is rigid and continuous, and the threaded joints with listed fittings create tight, weatherproof seals. Its metal path also supports reliable grounding/bonding for the service equipment, which is important when the enclosure is outdoors.

Other options lack this combination of rugged protection and a reliable metal ground path in exposed outdoor environments. Nonmetallic conduit and PVC can be weather-resistant in some cases but aren’t uniformly specified for weather-exposed service enclosures, and flexible metallic conduit doesn’t provide the same long-term weatherproof protection or rigidity for exterior service connections.